Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
Processing...

Test String

Code Generator

Language

Generated Code

$re = '/^yahoo\.com?(?:(?!\.[a-z]{2}).)*(?:.com?)?$ /mi'; $str = 'STACK ANSWER ^yahoo\\.com?(?:(?!\\.[a-z]{2}).)*(?:.com?)?$ ?: NON CAPTURING GROUP - uses this to match but doesn\'t include ?! NEGATIVE LOOKAHEAD - use this to look ahead to anything dot (2 chars) dot (IE .fr.) . ANY CHARACTER * UNLIMITED # TIMES ?: use this to match : .com? (m is optional) (expression is optional) $ ends com.fr (followed by anything)* with optional .co OR .com .co.kr KEEP yahoo.es yahoo.fr yahoo.ca yahoo.cm yahoo.cn yahoo.tw yahoo.co.jp yahoo.co.kr yahoo.co.uk yahoo.com.cn yahoo.com.hk yahoo.com.mx yahoo.com.tw REPLACE yah.com yahaoo.com yahho.com yahhoo.com yaho.com yahoo yahoo,com yahoo.c yahoo.co yahoo.co, yahoo.com yahoo.com, yahoo.com. yahoo.com\' yahoo.com/haltokariev yahoo.com> yahoo.com21yahoo.com yahoo.comcom yahoo.comheatdoc1123 yahoo.comj yahoo.comm yahoo.comn yahoo.comok.nicholastrami9-12-15 yahoo.comom yahoo.comy.net yahoo.con yahoo.coom yahoo.copm yahoo.cvom yahoo.net yahoo.ocm yahoo.om yahooc.om yahoocom yahoogroups.com yahool.com yahoomail.com yahooo.com '; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php